Contact us

Questions about the index, a value that looks wrong, a complaint, licensing or press: send us a message below or email c100index@protonmail.com. We reply within 5 business days.

Good to know

• Data or index errors: tell us the index or asset, the date and what looks wrong. Every close can also be recomputed on Verify the index.
• Complaints are acknowledged within 5 business days and answered in full within 30 days, as set out in the governance policy.
• Licensing (benchmarks, data, custom indexes): see License for the options.
• Developers: the public API and widgets are free to use.

We use what you send only to reply to you; see the privacy notice. The C100 gives no investment advice and can't answer questions about what to buy or sell.